The present invention relates to medical catheters and cannula, and more particularly to tracheal tubes.
Tracheal tubes have been used for some time to administer anesthesia to a patient, and to provide a bypass supply of air or mixture of gases to a patient having an obstruction in the upper area of the throat. Tracheal tubes can be in the form of a long flexible endotracheal tube wherein the distal end can be inserted into the trachea through the nose or mouth of the patient, or can be a short curved tracheostomy tube wherein the distal end can be inserted into the trachea through a surgical incision in the neck of the patient. The proximal end of the tracheal tube remains outside the trachea in communication with ambient air to permit passage of such air into the trachea.
The proximal end of the tracheal tube can also be attached to a respiratory device to assist the patient's breathing. The distal end typically includes an inflatable cuff as described in U.S. Pat. No. 3,659,612 which is inflated after the tube is positioned to provide a fluid seal between the distal end of the tube and the wall of the trachea. The inflatable cuff includes a thin film elastic balloon which is bonded around the tube, having an inflation line extending from the balloon to the proximal end of the tube, and can further include check valves, relief valves, and external bulb indicators to help maintain the desired pressure within the cuff. Excessive pressure in the cuff can cause severe damage to the wall of the trachea, and insufficient pressure can result in an inadequate seal. When the inflatable cuff is properly designed, manufactured, handled, and used, it performs a safe and effective fluid seal. A problem with the inflatable cuff is that the cuff and inflation line are costly and difficult to manufacture. Another problem is that the inflatable cuff is very delicate and easily damaged during handling and in use; any leak in the balloon, inflation line or check valve will allow the cuff to collapse and not provide an adequate seal.
U.S. Pat. No. 3,659,611 discloses an early non-inflatable tracheal tube seal, in which the distal end of the device includes a series of three resilient, solid disc, silicon flanges to engage the wall of the trachea. An apparent problem with the solid disc flanges is that the discs must be larger than the trachea to insure an occluding seal, but the oversized discs cannot conform to a smaller opening without bending and buckling around the periphery of the disc. The bending and buckling around the periphery of the discs can result in an ineffective seal, and can result in stress concentrations which may produce excessive localized pressure on the tracheal wall.
Other medical procedures often require placement and sealing of a small cannula or catheter within a body passageway, for example an arterial or venous catheter within a blood vessel. Such cannula may be difficult to seal and can require a "cut down" surgical procedure of the vessel, with clamps and sutures to adequately seal the cannula within the body passageway.
It is a object of the present invention to provide a safe, effective, reliable and durable fluid sealing cuff between a cannula and a body passageway.
It is another object to provide a non-inflatable sealing cuff for a tracheal tube which is not difficult and not expensive to manufacture; and safe, effective, reliable and durable in use.